5 USC 3324 – Appointments to positions classified above GS-15
(a) An appointment to a position classified above GS-15 pursuant to section 5108 may be made only on approval of the qualifications of the proposed appointee by the Director of the Office of Personnel Management on the basis of qualification standards developed by the agency involved in accordance with criteria specified in regulations prescribed by the Director. This section does not apply to a position—
(1) to which appointment is made by the Chief Judge of the United States Tax Court;
(2) to which appointment is made by the President;
(3) to which appointment is made by the Librarian of Congress; or
(4) the incumbent of which is paid from—
(A) appropriations for the Executive Office of the President under the heading “The White House Office”, “Special Projects”, “Council of Economic Advisers”, or “National Security Council”; or
(B) funds appropriated to the President under the heading “Emergency Fund for the President” by the Treasury, Post Office, and Executive Office Appropriation Act, 1966, or a later statute making appropriations for the same purpose.
(b) The Office may prescribe regulations necessary for the administration of this section.